Air drying unit



J. H. HENDERSON July 8, 1969 AIR DRYING UNIT Sheet Filed May 27, 1968 INVENTOR JOSEPH H. HENDERSON AT TO RNEY July 8, 1969 J. H- HENDERSON AIR DRYING UNIT Sheet Z of 2 Filed May 27-, 1968 INVENTOR JOSEPH H. HENDERSON I ATTORNEY United States Patent US. Cl. 55269 3 Claims ABSTRACT OF THE DISCLOSURE An improved air drying unit characterized by a shell having upper and lower stages therein, first and second spaced high conductivity heat exchangers extending vertically between said upper and lower stages and forming foraminous walls to define three chambers for movement of air past said heat exchangers, said shell and one of said stages providing a passageway for entrant air to the first of said heat exchangers for warming air above its dewpoint which hs been cooled below its dewpoint in the second of said heat exchangers, said shell and other of said stages providing apassageway for air moving from the first to the second of said heat exchangers to cool said aid below its dewpoint in the second of said heat exchangers by heat exchange with an expanded refrigerant, and a central chamber between said heat exchangers having means therein for separating water from the air which has been cooled below its dewpoint in the second of said heat exchangers.

The structure according to the present invention finds particular application in industrial plants requiring large quantities of compressed air which must be dry and free from entrained foreign material such as oil. By reason of the structure herein disclosed it is possible to provide complete drying of the air. in 20% of the space required for conventional kinds of equipment. For example, conventional equipment employing standard heat exchange devices with conventional high K factors and capable of handling 1750 c.f.m. of air has required a space having parameters of 120 x 120 x 84 or a total of 700 c.f. On the other hand, the structure herein, by reason of high conductivity heat exchangers and the placement thereof in the manner as now taught, is capable of handling 3200 c.f.m. in a space 72" x 82" x 34", or 116 c.f.

With the foregoing considerations in mind it is a principal object of the invention to provide a highly efiicient air drying structure occupying but a fraction of the space required by conventional structures.

Another object is to provide an air dryer contained within a single shell having upper and lower stages therein and defining with the shell passageways for the movement of air, the upper and lower stages defining with first and second spaced high conductivity heat exchangers, chambers for the movement of air past the heat exchangers and for the detraining of water from air lowered in temperature below its dewpoint after moving past one of the heat exchangers.

In the drawings:

FIG. 1 is an elevation view of an air drying apparatus embodying the principles according to the present invention;

FIG. 2 is a plan view thereof:

FIG. 3 is a section along the line 3-3 of FIG. 2 looking in the direction of the arrows;

FIG. 4 is an elevation view of one of the high conductivity heat exchangers, looking in the direction of the arrows 4-4 of FIG. 3; and I FIG. 5 is a section through the other of such heat exchangers, looking in the direction of the arrows 5-5 of FIG. 3.

3,453,809 Patented July 8, 1969 Referring to FIGS. 1 and 2, the improved air dryer according to the present invention is denoted by the reference numeral 10 and is incorporated in a unit comprised of a prefilter 11 for compressed air connected by a pipe 12 to a cylindrical vessel or shell 13. The latter is mounted on a frame 14 comprised of a base 16, vertical corner posts 17, and stringer members 18 extending between pairs of such corner posts 17. Transverse saddle members 19 extend between the stringer members 18 and support vessel 13 thereon.

A water cooled motor driven compressor-condenser unit 21 is supported on base 16 beneath vessel 13, and

has a water cooled condenser 22 supplied with cooling water at connections 22 and 23.

Referring to FIG. 3, the vessel or shell 13 has an entrance fiange 24 at the top thereof for connection of the pipe 12 thereat, for movement into the shell of air which has moved past the prefilter 11. Upper and lower stages 26 and 27 extend lengthwise of the shell 13 and respectively define a passageway 28 for entrant air, and a passageway 29 for air moving between the heat exchangers.

Stage 26 is welded along its sides and ends to the inside of shell 13, and is additionally secured in position by a web 31 extending lengthwise of the interior of shell 13. Stage 27 is similarly held within shell 13, and is additionally held by webs 32 also extending lengthwise in the fashion as web 31.

First and second spaced high conductivity heat exchangers 33 and 34 extend vertically between the spaced stages 26 and 27 so as to define foraminous walls between three chambers designated generally by reference numerals 36, 37 and 38. Each of the heat exchangers is of the same general type as seen in FIGS. 4 and 5, and in the case of heat exchanger 33, it is composed of long flattened copper tubes 39 supported in a matrix of small copper shot 41 sintered together and also sintered to the walls of the tubes 39. A typical section through such heat exchanger 33 is shown in FIG. 5, and they may be arranged in'banks of desired thickness, and extending for the length of the shell 13 as seen in FIG. 3.

The second heat exchanger 34 is substantially like heat exchanger 33, but is arranged with upper and lower headers 42 and 43. Gaseous refrigerant is introduced to the lower header 43 by a supply pipe 44 connected to motor compressor condenser unit, and moves upward through the tubes 39 to the header 42, whence the heated and expanded refrigerant exits via a return line 46 to return to u'iiit 21.

p, where the air is cooled by air moving through the forarninae thereof and from the exchanger 34 which is raised Compressed and filtered air entering passageway 28 moves through the passageways 39 of heat exchanger 33 in its temperature at heat exchanger 33 above its dew point. Such tempered air exits from chamber 36 via an outlet pipe 48. The air passing through the passages 39 of heat exchanger 33 moves via passageway 29 in shell 13, through openings 49 in the web members 32 and into the chamber 38. The air then moves through the interstices between the sintered copper balls of heat exchanger 34 "and in heat exchange relationship with the refrigerant moving in the tubes 39 of such heat exchanger.

51 and 52 are spaced in the manner shown and support therebetween suitable moisture trapping structure 53. In the embodiment herein shown, such structure 53 may be in the form of aluminum mesh folded and leaved upon itself to present tortuous passages for the moisture laden air below its dewpoint and emerging from heat exchanger 34. The moisture wrung out from such air falls from the structure to the stage 27 which is sloped in the manner shown to create a sump where the water collects. An automatic drain valve, not shown, is operable to discharge the sump to a drain pipe 54.

I claim:

1. In an improved air drying unit, a shell having upper and lower stages therein, first and second spaced high conductivity heat exchangers each including a plurality of tubes and extending vertically between said upper and lower stages and said upper and lower stages forming foraminous walls to define three chambers for movement of air into and past said heat exchangers, said shell and one of said stages providing a passageway for entrant air to the first of said heat exchangers for warming air above its dew point which has been cooled below its dew point in the second of said heat exchangers, said shell and the other of said stages providing a passageway for air moving from the first to the second of said heat exchangers having means therein for separating water from the air which has been cooled below its dew point in the second of said heat exchangers, said shell being provided with an exit passage communicating with the separating means through said first heat exchanger to heat exchange the inlet and outlet air streams.

2. The air drying unit of claim 1 wherein said central chamber is provided with spaced baffles through which the cooled air must travel, and wherein said bafiles support said water separating means.

3. The air drying unit of claim 1, wherein said lower stage is constructed with a sump therebelow to receive water separated by said separating means.

References Cited UNITED STATES PATENTS 1,592,848 7/1926 Hack 62507 2,257,983 10/1941 Shipman 80 2,281,168 4/1942 Paget -166 3,096,630 7/1963 Weller 62506 3,129,077 4/ 1964 Adams 55269 3,165,387 l/1965 Place.

HARRY B. THORNTON, Primary Examiner.

B. NOZICK, Assistant Examiner.

US. Cl. X.R. 

